from __future__ import absolute_import, unicode_literals
import json
import datetime
import six

from decimal import Decimal

from django.core.exceptions import ValidationError
from django.conf import settings
from django.db import models
from django.utils.translation import ugettext_lazy as _

from sentry.db.models.utils import Creator


def default(o):
    if hasattr(o, 'to_json'):
        return o.to_json()
    if isinstance(o, Decimal):
        return six.text_type(o)
    if isinstance(o, datetime.datetime):
        if o.tzinfo:
            return o.strftime('%Y-%m-%dT%H:%M:%S%z')
        return o.strftime("%Y-%m-%dT%H:%M:%S")
    if isinstance(o, datetime.date):
        return o.strftime("%Y-%m-%d")
    if isinstance(o, datetime.time):
        if o.tzinfo:
            return o.strftime('%H:%M:%S%z')
        return o.strftime("%H:%M:%S")

    raise TypeError(repr(o) + " is not JSON serializable")


class JSONField(models.TextField):
    """
    A field that will ensure the data entered into it is valid JSON.

    Originally from https://github.com/adamchainz/django-jsonfield/blob/0.9.13/jsonfield/fields.py
    Adapted to fit our requirements of:

    - always using a text field
    - being able to serialize dates/decimals
    - not emitting deprecation warnings
    """
    default_error_messages = {
        'invalid': _("'%s' is not a valid JSON string.")
    }
    description = "JSON object"

    def __init__(self, *args, **kwargs):
        if not kwargs.get('null', False):
            kwargs['default'] = kwargs.get('default', dict)
        self.encoder_kwargs = {
            'indent': kwargs.pop('indent', getattr(settings, 'JSONFIELD_INDENT', None))
        }
        super(JSONField, self).__init__(*args, **kwargs)
        self.validate(self.get_default(), None)

    def contribute_to_class(self, cls, name):
        """
        Add a descriptor for backwards compatibility
        with previous Django behavior.
        """
        super(JSONField, self).contribute_to_class(cls, name)
        setattr(cls, name, Creator(self))

    def validate(self, value, model_instance):
        if not self.null and value is None:
            raise ValidationError(self.error_messages['null'])
        try:
            self.get_prep_value(value)
        except BaseException:
            raise ValidationError(self.error_messages['invalid'] % value)

    def get_default(self):
        if self.has_default():
            default = self.default
            if callable(default):
                default = default()
            if isinstance(default, six.string_types):
                return json.loads(default)
            return json.loads(json.dumps(default))
        return super(JSONField, self).get_default()

    def get_internal_type(self):
        return 'TextField'

    def db_type(self, connection):
        return 'text'

    def to_python(self, value):
        if isinstance(value, six.string_types):
            if value == "":
                if self.null:
                    return None
                if self.blank:
                    return ""
            try:
                value = json.loads(value)
            except ValueError:
                msg = self.error_messages['invalid'] % value
                raise ValidationError(msg)
        # TODO: Look for date/time/datetime objects within the structure?
        return value

    def get_db_prep_value(self, value, connection=None, prepared=None):
        return self.get_prep_value(value)

    def get_prep_value(self, value):
        if value is None:
            if not self.null and self.blank:
                return ""
            return None
        return json.dumps(value, default=default, **self.encoder_kwargs)

    def get_prep_lookup(self, lookup_type, value):
        if lookup_type in ["exact", "iexact"]:
            return self.to_python(self.get_prep_value(value))
        if lookup_type == "in":
            return [self.to_python(self.get_prep_value(v)) for v in value]
        if lookup_type == "isnull":
            return value
        if lookup_type in ["contains", "icontains"]:
            if isinstance(value, (list, tuple)):
                raise TypeError("Lookup type %r not supported with argument of %s" % (
                    lookup_type, type(value).__name__
                ))
                # Need a way co combine the values with '%', but don't escape that.
                return self.get_prep_value(value)[1:-1].replace(', ', r'%')
            if isinstance(value, dict):
                return self.get_prep_value(value)[1:-1]
            return self.to_python(self.get_prep_value(value))
        raise TypeError('Lookup type %r not supported' % lookup_type)

    def value_to_string(self, obj):
        return self._get_val_from_obj(obj)


if 'south' in settings.INSTALLED_APPS:
    from south.modelsinspector import add_introspection_rules
    add_introspection_rules([], ['^sentry\.db\.models\.fields\.jsonfield.JSONField'])
